[Bug classpath/28619] New: NIO is incomplete

[csm at gnu dot org]

Our NIO implementation -- especially socket channels -- is currently
incomplete; the implementation we have relies on plain, blocking-IO sockets to
implement channel operations (and, it does this by relying on socket timeouts
to "emulate" nonblocking behavior). This solution won't work for all cases.

Specific issues with the current implementation include nonblocking connects
not working, and neither does detecting EOF on a nonblocking read.

I don't think it's possible, or at least, wise, to try to use PlainSocketImpl
to implement nonblocking sockets; that code (aside from suffering from the
target-native brain damage) is far too reliant on the blocking model, and it
looks difficult to teach it to handle nonblocking IO too. The current
implementation is, at best, barely adequate.

The best solution, that I can think of, is to put the maybe-blocking operations
 (read, write, connect and accept) exclusively in the SocketChannelImpl class,
to put the socket option manipulation in the PlainSocketImpl class, and to make
blocking sockets just call to a private SocketChannel for IO operations.


-- 
           Summary: NIO is incomplete
           Product: classpath
           Version: 0.92
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: classpath
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: csm at gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28619